1. Field of the Invention
The present invention relates to the removal of manganese from aqueous industrial waste effluents. The present invention particularly relates to the removal of manganese from industrial waste effluents containing other heavy metals and fluoride.
The Federal Environmental Protection Agency (EPA) has set Federal Guidelines for the standards and effluent limitations of pollutants discharged into navigable waters and into publicly owned treatment works. A particularly difficult problem has been the removal of manganese and other heavy metals from aqueous industrial waste effluents. The heavy metals depending on the industrial process involved may also contain pollutants such as fluoride and phosphorous which must also be controlled.
One of the industries now receiving attention is the aluminum can industry, i.e. the manufacture of aluminum cans. A step in the manufacture of aluminum cans is an acid fluoride wash or an alkaline (non-fluoride) wash.
The principle pollutants in the aqueous wash water waste effluent from aluminum can manufacturing plants are heavy metal ions such as aluminum, chromium, copper, iron, zinc and manganese, and anions such as fluoride and phosphorous, and oil and grease. The pollutants that are the most difficult to remove are manganese and fluoride.
The oil and grease removal and control needed will depend on the plant lubricant system used and will generally be carried out in a separate step, depending on the concentration of oil and grease in the effluent. The oil and grease removal step, when needed, can be carried out before or after the removal of heavy metals and fluoride.